A. Field of Invention
This invention generally relates to methods and apparatuses concerning the shaping of tires in tire molds and more specifically to methods and apparatuses concerning the direct measurement of pressure on a tire going through a shaping process and/or a curing process.
B. Description of the Related Art
It is long known to manufacture a tire using the following method: (1) construct a green (uncured) tire on a tire building drum; (2) insert the green tire into a tire mold; (3) close the tire mold around the green tire; (4) shape the green tire against the tire mold with a bladder; (5) vulcanize the green tire into a cured tire with a curing press; and, (6) open the mold and remove the cured tire.
Understanding and controlling the tire shaping process is important to ensure proper tire component positions and gauges, and consequently tire uniformity and performance. One important aspect of the shaping process is the specific pressure exerted on the tire by the bladder and by the mold. Given the relatively high pressures and temperatures that are used in shaping a tire, it has proven to be very difficult to determine with accuracy the pressures involved. Similarly, it has proven to be very difficult to determine with accuracy the pressures involved in curing a tire. It is only known to use indirect methods to determine these pressures—such as using thermocouples where a sudden temperature jump indicates the onset of contact.
What is needed is a way to directly determine the pressures exerted on a tire during the shaping process and/or during the curing process.